Logging while raising a drill string

Abstract

In logging a well substantially as soon as it is drilled, at least one measuring transducer and a transducer-moving system are mounted within a lower portion of a segmented electrically-conductive drill string. At least one downhole transducer is moved in response to an electrical command and is held near or against the borehole wall while the drill string is raised and a recording is made of electrical signals indicative of both the downhole transducer measurements and the distance the drill string is raised.

What is claimed is: 
     
       1. A process for drilling and logging a downwardly extending well borehole comprising: drilling the borehole with a signal transmissive drill string which contains a magnitude-responsive transducer which, during the drilling, is kept at least substantially within the external confines of the drill string;   movably-mounting said transducer within a lower portion of the drill string and mechanically connecting it to a motion-imparting means which is capable of being actuated by a command signal transmitted along the drill string to urge the transducer toward or away from an extended position at least substantially in contact with the wall of a borehole drilled by the drill string or a retracted position at least substantially within the exterior confines of the drill string;   stopping the drill string and transmitting along it a command signal that initiates the urging of the magnitude-responsive transducer toward its extended position;   raising the drill string while transmitting along it a signal indicative of the magnitude at which a subterranean physical or chemical property is encountered by the magnitude-responsive transducer while it is in contact with, or in close proximity to, the borehole wall;   operating a movement-responsive transducer to provide a signal indicative of the distance by which the drill string is raised;   providing a record of the variation with depth in said subterranean property; and,   stopping the drill string and transmitting along it a command signal that initiates the urging of the magnitude-responsive transducer toward its retracted position.   
     
     
       2. The process of claim 1 in which: the magnitude-responsive transducer is mechanically connected to the motion-imparting means by a resilient linking-means;   the motion-imparting means is operated to move one portion of the resilient linking-means by a distance sufficient to press the transducer against one side of the borehole when the drill string is pressed against the opposite side; and,   the resilient linking-means is arranged so that, in response to said movement, the force transmitted to the transducer is sufficient to move the transducer, when its movement is not prevented by the borehole wall, but is insufficient to move or damage the transducer or the means by which it is moved or mounted when the transducer-containing portion of the drill string is pressed against the wall of the borehole.   
     
     
       3. The process of claim 1 in which: an inward biasing force is applied to continually urge the transducer toward its retracted position; and,   the force provided by the motion-imparting means urges the transducer toward its extended position by overriding the biasing force.   
     
     
       4. The process of claim 1 in which the borehole is drilled by rotating the drill string to drill about the length of the pipe section, stopping it to add a new pipe section, then resuming the drilling operation, and the initiating of the steps of urging of the magnitude-responsive transducer toward its extended position, raising the drill string while logging, and urging the transducer toward its retracted position, are initiated at a time at which the addition of a section of drill string is desirable. 
     
     
       5. The process of claim 1 in which electrical command and magnitude-responsive data signals are transmitted along the lower portion of the signal-transmissive drill string by means of a remotely connectable wire line and are transmitted along the upper portion of that drill string by means of an insulated electrical conductor that extends through and across the joints of a series of interconnected drill pipe sections. 
     
     
       6. A well logging instrument-containing drill collar section which is capable of being incorporated into a signal-transmissive drill string containing a plurality of drill pipe and collar sections, comprising: a drill collar section which contains an internal fluid passageway and at least one groove extending longitudinally along the exterior of the section;   within said groove, a movably-mounted magnitude-responsive transducer which is mechanically connected to a motion-imparting means which is capable of being actuated by command signal transmitted along the drill string to urge the transducer toward or away from an extended position at least substantially in contact with the wall of the borehole drilled by the drill string or a retracted position at least substantially within the external confines of the drill string;   within said drill collar section, a signal-transmissive means for transmitting to the motion-imparting means the signals from a means for transmitting along the drill string a command signal for initiating the urging of the magnitude-responsive transducer toward its extended position; and   within said drill collar section, a signal-transmissive means for transmitting along the drill string a signal indicative of the magnitude of a subterranean property encountered by the magnitude-responsive transducer.   
     
     
       7. The apparatus of claim 6 in which: the magnitude-responsive transducer is mechanically connected to the motion-imparting means by a resilient linking-means;   the motion-imparting means is arranged to move one portion of the resilient linking-means by a distance sufficient to press the transducer against one side of said borehole wall while the drill string is pressed against the opposite side;   the resilient linking-means is arranged so that, in response to said movement, the force transmitted to the transducer is sufficient to move the transducer when movement is not prevented by the proximity of the borehole wall, but is insufficient to move or damage the transducer, or the means by which it is moved or mounted, when the transducer-containing portion of the drill string is pressed against the wall of the borehole.   
     
     
       8. The drill collar section of claim 7 in which: said motion-imparting means is arranged to apply an extending motion to the resilient linkage-means; and   the resilient linking-means consists essentially of an extendable spring.   
     
     
       9. The drill collar section of claim 6 in which: the magnitude-responsive transducer is mounted on a resilient member on which a biasing force is applied in a direction tending to urge the transducer toward its retracted position; and,   the motion-imparting means is arranged to move the transducer toward its extended position by overriding said biasing force.   
     
     
       10. The drill collar section of claim 6 in which: said drill collar section contains an electrical conductor capable of being remotely connected to a wire line; and,   said signal-transmissive drill string is arranged for the transmission of electrical command and magnitude-responsive data signals along its lower portion by means of a remotely connectable wire line and the transmission of such signals along its upper portion by means of a segmented insulated electrical conductor extending along each of a series of electrical conductor-containing drill pipe sections.